If you see a small problem, fix it now rather than waiting. Small problems can develop into larger problems. If you see a nail pop, go ahead and fix it. It might require some Spackle and paint, but it'll be worth it in the long run.
Clean your dryer vent at least once every 6 months. I'm not talking about the vent on the dryer itself. I'm talking about the vent from the dryer to the outside. So much gunk can build up in that passageway.
Pressure wash your home at least once a year, if not more. Be mindful of the tips and the pressure you are using. I would not use a pressure washer on a treated deck unless you know what you're doing. You run the risk of splintering the wood, or making it "fuzzy".
Try and maintain any shrubs that border your home.
I completely agree with the gutter thing. Having clogged gutters can absolutely ruin your landscaping, as well as cause major runoff issues. I can speak first hand about that one.
I would have your AC unit inspected at least yearly as well. I have a newer house, but I still have this done. The piece of mind is worth the small cost.